Personal protection system

ABSTRACT

A personal protection system is mountable to a user for distributing air to the user includes a shell providing structure. A fan module is supported by the shell for generating a flow of air. Cushioning is provided between the fan module and the shell to reduce vibrations and noise. The fan module includes a fan with blades having an airfoil shape for added noise reduction. An air flow channel is in fluid communication with the fan module for routing the flow of air. A pair of nozzle tips are in fluid communication with the air flow channel and are rotatably adjustable to allow directional adjustment of the flow of air toward a neck of the user. The personal protection system also includes a face shield with multiple removable layers which are sterilized as a unit using gamma radiation.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of provisional application Ser. No.60/664,900 filed Mar. 24, 2005, which is hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention generally relates to a personal protection systemmountable to a user for distributing air to the user. The personalprotection system is utilized in the medical profession during surgicalprocedures. The subject invention more specifically relates to a helmetassembly and gown for use in the personal protection system.

2. Description of the Prior Art

Personal protection systems and helmet assemblies utilized in personalprotection systems are known in the art. As indicated above, personalprotection systems and helmet assemblies are worn by users throughoutthe medical profession, such as surgeons, during surgical procedures.

Conventional personal protection systems and helmet assemblies aredeficient for one reason or another. For example, U.S. Pat. No.6,990,691 to Klotz et al. (the '691 patent) discloses a helmet assemblythat draws air in with a fan assembly and distributes the air to frontand rear air exits. However, when the helmet assembly is worn by theuser, the air exit is disposed such that the air is vented near themiddle of the back of the head of the user. Thus, the air cannot bedirected toward the neck of the user, where most surgeons desire theair's cooling presence.

Other deficiencies of prior art personal protection systems are with thefan assembly. For instance, the shape of the blades of the fan, whichrotate to draw in air, do not provide for the most efficient andquietest flow of air possible. This causes excessive power consumption,which leads to premature drain of battery packs, and excessive noise,which can be distracting for a surgeon performing delicate operations.

Furthermore, the prior art helmet assemblies tend to transfer vibrationscaused by the rotation of the fan to the user, as well as being noisy ingeneral. The vibrations, as well as the noise, can be distracting to thesurgeon, who obviously needs to focus his efforts at the complex task athand.

Yet another deficiency of the '691 patent concerns the multipleremovable layers disposed on the face shield. The '691 patent is silentas to sterility of the multiple removable layers. However, sterilizationconcerns are of an utmost importance for any product involved in thesurgical process.

For the above mentioned reasons, it is desirous to provide a personalprotection system which provides more control over air flow to the neckof the user and which provides more efficient and quieter means formoving the flow of air. Furthermore, it is desirous to provide apersonal protection system which noise and vibrations, which can bedistracting to the surgeon, are kept to a minimum. Moreover, it isdesirous to provide a face shield with removable layers that issterilized in an efficient manner.

SUMMARY OF THE INVENTION AND ADVANTAGES

In a first aspect of the invention, a personal protection unit isdisclosed. The personal protection unit includes a support structure forsuspending a hood over the head of an individual. A fan module isattached to the support structure, with the fan module receiving air anddischarging air. A duct is connected to the support structure and has anopening positioned to receive the air discharged from the fan module.The duct is shaped to have a rear air exit. The duct is arrangedrelative to the fan module so that only a fraction of the air dischargedfrom the fan module enters the duct. The duct extends from the supportstructure and the rear air exit is positioned so that air is dischargedfrom the rear air exit directly onto the neck of the individual. By theduct extending from the support structure and discharging air directlyon to the neck, the comfort of the individual (e.g., a surgeon) isincreased, allowing the individual to focus on the task he or she isperforming (e.g., surgery).

In a second aspect of the invention, the personal protection unitincludes the support structure for suspending the hood over the head ofthe individual. The personal protection unit includes a fan forcirculating air. A motor is attached to the support structure and isconnected to the fan for actuating the fan. An elastomeric, vibrationdampening member holds the motor to the support structure. The vibrationdampening member helps to reduce transmission of noise and/or vibrationsgenerated by the fan and/or motor to the user. Reduction of noise and/orvibrations will decrease distractions to the individual.

A third aspect of the subject invention provides the personal protectionsystem with the hood formed of flexible sterilizable material, a portionof which is filter material, and shaped to be worn over the head. Atransparent face shield is attached to the hood. The personal protectionsystem includes a support structure for suspending the hood over thehead. A fan is attached to the support structure for circulating airthrough the hood. A plurality of individually removable layers ofsterile transparent material are disposed over the face shield.

A fourth aspect of the invention provides a method of assembling asterilized hood assembly having a transparent face shield. The methodincludes the step of providing a hood formed from sterilizable flexiblematerial, a portion of the material being filter material. A transparentface shield assembly is attached to the hood where the shield assemblyincludes a face shield. The method further includes the step ofsterilizing the hood and face shield assembly using a sterilizationprocess that does not adversely affect the filter material. Thetransparent shield assembly further includes a plurality of removabletransparent layers disposed over the face shield. Sterilizing the faceshield and removable layers together as a whole provides for a moreeffective assembly process by negating the possibility of introducingcontaminants during subsequent assembly operations.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated,as the same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view of a personal protection system embodied asa helmet assembly mounted on a head of a user;

FIG. 2 is a cross-sectional view of the helmet assembly;

FIG. 3 is an exploded perspective view of the helmet assembly;

FIG. 4 is an exploded view of a preferred embodiment of a fan module ofthe present invention;

FIG. 5 is a cross-sectional view of the preferred embodiment of the fanmodule;

FIG. 6 is a cross-sectional view of an alternative embodiment of the fanmodule;

FIG. 7 is a perspective view of a fan of the fan module showing fanblades having an airfoil shape.

FIG. 8 is a top view of the fan showing the fan blades having air foilshapes;

FIG. 9 is a elevational view of a nozzle assembly of the presentinvention;

[0023] FIG. 10 is a perspective view of a nozzle tip of the nozzleassembly;

FIG. 11 is a bottom view showing a port of a nozzle of the nozzleassembly;

FIG. 12 is an exploded view of a first alternative nozzle of the presentinvention and a first adjustable air flow volume mechanism;

FIG. 13 is an exploded view of a second alternative nozzle of thepresent invention and a second adjustable air flow volume mechanism;

FIG. 14 is a perspective view a hood having an integrated face shieldattached to the helmet assembly; and

FIG. 15 is an elevational view of a removable face shield layer attachedto the face shield.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figures, wherein like numerals indicate correspondingparts throughout the several views, a personal protection system orpersonal protection unit is generally shown at 20. The personalprotection system 20 is mountable to a user (i.e., an individual) fordistributing air to the user. The personal protection system 20 of thepresent invention is adapted from the personal protection systemsdisclosed in U.S. Pat. No. 6,481,019 to Diaz et al. (the '019 patent)and U.S. Pat. No. 6,973,677 to Diaz et al. (the '677 patent), which arehereby incorporated by reference.

In the preferred embodiment, as shown in FIG. 1, the personal protectionsystem 20 is implemented as a helmet 22 or helmet assembly 22. Thepersonal protection system 20 filters air between a head 24 and body 26of a user, e.g., a medical professional, and an environment external tothe user. When in use, the preferred helmet assembly 22 of the personalprotection system 20 is mounted to the head 24 of the user. The helmetassembly 22 distributes air about the head 24 of the user as will bedescribed below. More specifically, in the preferred embodiment, thehelmet assembly 22 distributes air toward both a front of the head 24,i.e., a face of the user, and a back of the head 24, i.e., a neck of theuser.

The personal protection system 20 of the subject invention may bedescribed hereafter in terms of the helmet assembly 22 of the preferredembodiment. However, this should not be construed as limiting thepersonal protection system 20 to the helmet assembly embodiment.

Referring to FIG. 2, the helmet assembly 22 includes a shell 28providing structural support (i.e., a support structure 28). The shell28 preferably includes an inner shell portion 30 facing the user and anouter shell portion 32 facing away from the user. In the preferredembodiment, the outer shell portion 32 is spaced apart from the innershell portion 30 to define at least one air flow channel 34 between theinner and outer shell portions 30, 32. It is to be understood that thepresent invention may include more than one discrete air flow channel34. However, the preferred embodiment includes a single unitary air flowchannel 34 and the present invention will be described below in terms ofthis air flow channel 34. The shell 28 is preferably formed ofacrylonitrile butadiene styrene (ABS), but may be formed, in alternativeembodiments, of glass-filled polypropylene or other suitable materials.

The air flow channel 34 channels air about the head 24 of the user. Theinner and outer shell portions 30, 32 may form the air flow channel 34from a two-sheet thermoforming process which improves the structuralstrength of the shell 28. More specifically, each of the inner and outershell portions 30, 32 include an outer periphery, and in the two-sheetthermoforming process, the inner and outer shell portions 30, 32 arepinched together at their outer peripheries. The air flow channel 34 issubsequently thermoformed between the pinched outer peripheries.

The helmet assembly 22 also includes a facial section 36 extending fromthe shell 28 to define a facial opening 38. The facial section 36 of thehelmet assembly 22 is a chin bar 40. Preferably, the chin bar 40 isflexible and is formed of plastic. The chin bar 40 may also be formed ofa polypropylene component. The flexibility of the chin bar 40 protectsthe user's face and also absorbs impact when the user contacts anexternal object with the helmet assembly 22.

Referring now to FIG. 3, the helmet assembly 22 includes a fan module 42supported by the shell 28. More specifically, the fan module 42 ismounted in a cavity 44 formed by the shell 28. The fan module 42operates to generate a flow of air which is fluidly communicated intothe air flow channel 34. As shown in FIG. 4, the fan module 42 includesa fan 46 and a motor 48 mounted to a scroll housing 50. The motor 48includes a drive shaft 52 operatively connected to the fan 46 to drivethe fan 46 at a plurality of rotational speeds correlating to an amount,or a volume, of air flowing into the air flow channel 34. As appreciatedby those skilled in the art, the rotational speeds of the fan 46 can bemeasured in revolutions per minute (RPMs).

Referring again to FIG. 3, a cover plate 54 is fixed to the shell 28 andthe fan module 42 to hold in the fan module 42 in the cavity 44. A fanmodule cushion 56 is disposed between the cover plate 54 and a base ofthe fan module 42. The fan module cushion 56 reduces the transmission ofnoise from the motor 48 to the user.

Referring to FIGS. 4 and 5, in the preferred embodiment, a motor cushion58 is disposed between the motor 48 and a motor mount 60. A plurality ofmotor mount cushions 62, embodied as grommets, is placed between themotor mount 60 and the scroll housing 50 (although shown below thescroll housing 50 for clarity, the arrangement is best shown in FIG. 5).The motor cushion 58 and motor mount cushions 62 work together as avibration dampening member to reduce shock loads and vibrations. Morespecifically, the motor mount cushions 62 are the primary component forshock reduction between the helmet structure, e.g., shell 28, and themotor 48, thereby extending the bearing life of the motor 48 andproviding low sound characteristics. The motor mount cushions 62completely isolate the motor 48 from the rest of the helmet structure.By having two sets of cushioning, i.e., the motor cushion 58 between themotor 48 and motor mount 60 and the motor mount cushions 62 between themotor mount 60 and the scroll housing 50, the transmission of energybetween the helmet structure and the motor 48 can be fine tuned. Themotor cushion 58 and the motor mount cushions 62 may be formed of foamand/or an elastomeric material.

Referring to FIG. 6, in an alternative embodiment of the invention, themotor mount 60 for mounting the motor 48 to the scroll housing 50 isformed of elastomeric material. Preferably, the motor mount 60 is formedof silicone having a durometer of from 10 to 80 shore A. Much like themotor mount cushions 62 of the preferred embodiment, the elastomericmotor mount 60 reduces shock loads and vibrations. Moreover, the scrollhousing 50 may be formed of glass-filled polypropylene to further reducevibrations.

Referring now to FIG. 7, the fan 46 includes a plurality of curvedblades 64 and a hub portion 66. The curved blades 64 of the fan 46encourage air into the scroll housing 50. The blades 64 are furtherdefined as centrifugal fan blades having a foil cross-section, i.e., theblades 64 taper along their length. This configuration moves air moreefficiently and more quietly than blades 64 with a constant thickness.The foil cross-section of each of the blades 64 preferably has an angleof attack of from 30 to 50 degrees. The fan 46 is preferably formed ofglass-filled polypropylene, more preferably 30% glass-filledpolypropylene.

Referring back to FIG. 4, the scroll housing 50 includes a base portion68 and an outer wall 70 circumferentially extending around the baseportion 68. The outer wall 70 includes an upper edge 72. The scrollhousing 50 further includes at least one air inlet 74 and at least oneair outlet 76. In the preferred embodiment, the scroll housing 50includes a plurality of air outlets 76, i.e., at least two air outlets76. Other embodiments of the present invention (not shown) may also onlyinclude the fan module 42 without the scroll housing 50. In suchembodiments, the at least one air inlet 74 and the at least one airoutlet 76 can be described as components of the fan module 42.

The scroll housing 50 of the preferred embodiment may include aninclined surface 78 (or cutoff) along the outer wall 70 at one or moreof the air outlets 76. The inclined surface 78 in the preferredembodiment is inclined relative to a rotational axis of the fan 46 andmotor 48. The inclined surface 78 moves air more efficiently through theair outlet 76. In effect, a blade-pass frequency at each air outlet 76employing the inclined surface 78 is altered such that at least twoblades 64 pass the air outlet 76 simultaneously. The outer wall 70 ispreferably wrapped outwardly away from the fan 46 at the outlet with theinclined surface 78 such that a flange portion 80 of the outer wall 70defines the inclined surface 78. Preferably, the outer wall 70 isrounded at the flange portion 80 to provide a smooth transition to theair outlet 76. This reduces noise from the air flowing through the airoutlet 76.

Referring again to FIG. 2, the helmet assembly 22 further includes anintake grid 82 mounted to the outer shell portion 32. The intake grid 82includes a top surface 84 spaced from the outer shell portion 32 of thehelmet assembly 22. The intake grid 82 is contoured to the outer shellportion 32 between the front and rear of the shell 28. Air is drawn intothe scroll housing 50 through the intake grid 82 by the fan 46. Theblades 64 of the fan 46 are dimensioned such that a top of each of theblades 64 is from about 0.14 to 0.20 inches below the upper edge 72 ofthe outer wall 70 of the scroll housing 50. This provides clearancebetween the blades 64 and the outer shell portion 32 above, whichresults in low noise and high efficiency.

The air inlet 74 of the scroll housing 50 is in direct communicationwith a hole 86 formed within the outer shell portion 32 of the shell 28for drawing air into the scroll housing 50. In alternative embodimentsof the present invention, an external structure, not shown in theFigures, can be mounted external to the helmet assembly 22 to establishthe air inlet 74 of the scroll housing 50 for drawing air into thescroll housing 50. The hole 86 formed in the outer shell portion 32 maybe circular in shape. The diameter of the hole 86 may be sized inrelation to a diameter of the fan 46 such that only a portion of the fan46 diameter is exposed when viewed through the air inlet 74 in the outershell portion 32. This ratio of air inlet 74 diameter to fan 46 diametermay be from 1:2 to 1:1, more preferably, from 1:1.5 to 1:1.1.

Referring to FIG. 4, a support pedestal 88 protrudes from the motormount 60. Preferably, the support pedestal 88 is integrally formed as apart of the motor mount 60, which is fixed to the base portion 68.Alternatively, it is also to be understood that the support pedestal 88can be a separate part. That is, the support pedestal 88 can be aseparate part that is mounted or connected to the base portion 68 of thescroll housing 50 via connecting screws, snap-fit, and the like. The hubportion 66 of the fan 46 is rotatably mounted in the scroll housing 50about the support pedestal 88. The motor 48 of the fan module 42 ismounted within an underside of the support pedestal 88 for space-savingpurposes in the helmet assembly 22. As appreciated, the underside of thesupport pedestal 88 is essentially hollow. The motor 48 shaft protrudesthrough an opening in the support pedestal 88 to rotatably engage thefan 46. The cover plate 54 operates as a motor 48 cover to close the fanmodule 42 at the inner shell portion 30. The motor 48 has a pair ofbearings, as will be appreciated by those skilled in the art. The fan 46is configured with a center of gravity that is centered between themotor 48 bearings. This reduces force moments about the motor 48bearings thus reducing stress to the motor 48 bearings. In essence,loads on the fan 46 are thus shared between the motor 48 bearings.

In operation, the motor 48 rotates the fan 46 to draw air into the airinlet 74 of the scroll housing 50 through the intake grid 82 and the airinlet 74 in the outer shell portion 32 and distributes air out of thescroll housing 50 through the air outlet 76 or outlets and into the airflow channel 34 where the air is distributed about the head 24 of theuser. Cutoffs (in some embodiments, inclined cutoffs as previouslydescribed) cut the air as the fan 46 moves the air within the scrollhousing 50. More specifically, as shown in the Figures, the presentinvention incorporates several air flow cutoffs in the scroll housing 50to cut the air. A power supply is incorporated in the present inventionto power the motor 48 to rotate the fan 46 via the motor 48 shaft.Preferably, the power supply is a rechargeable DC battery. Alsopreferred, the power supply is disposed within, i.e., integrated into,the helmet assembly 22. In such a case, the power supply is referred toas an integral power supply. Alternatively, the power supply can bemounted to the body 26 of the user (not shown). The power supply powersthe motor 48 through pulse width modulation (PWM) which will bediscussed further below. The design of the scroll housing 50 providesmore efficient movement of air with less power being required from thepower supply overall. Furthermore, in addition to such reduced powerrequirements, the scroll housing 50 provides that sufficient air flowcan be maintained with overall less air velocity. This results in aquieter helmet assembly 22.

With respect to the at least two air outlets 76, the outer wall 70 ofthe scroll housing 50 is partitioned to define the air outlets 76. Inthe preferred embodiment of the present invention having the at leasttwo air outlets 76, it is to be understood that the present invention isnot limited to at least two air outlets 76. That is, the presentinvention may include, for example, three or four air outlets 76. Theair outlets 76 provide a complete balance of air as the air isdistributed from the scroll housing 50 about the head 24 of the user. Toaccomplish this, the helmet assembly 22 includes at least two helmet airexits 90, 92 in fluid communication with the air flow channel 34. Theair outlets 76 are in fluid communication with the at least two helmetair exits 90, 92 to distribute the air from the air outlets 76, which isin the air flow channel 34, toward the head 24 of the user. In thepreferred embodiment of the present invention where the helmet assembly22 includes the at least two helmet air exits 90, 92 it is not criticalthat the scroll housing 50 include at least two air outlets 76. To thecontrary, the scroll housing 50, in these embodiments, may only have atleast one air outlet 76. Furthermore, the helmet assembly 22 may alsohave only one air exit.

In an alternative embodiment, at least one air bleed valve (not shown)may be incorporated in the scroll housing 50 to influence the amount, orthe volume, of air flowing into the air flow channel 34 from each of theair outlets 76. This is shown in the '019 patent to Diaz et al., whichis hereby incorporated by reference.

In the preferred embodiment, as best shown in FIG. 2, the air exits 90,92 are a front air exit 90 and a rear air exit 92 in that they aredisposed at a front section 94 and a rear section 96 of the helmetassembly 22, respectively, to effectively distribute air toward both theface and neck of the user. However, in alternative embodiments, the airexits 90, 92 can be disposed in alternate locations to distribute airtoward any portion of the user's head 24. For instance, the air exits90, 92 can be side air exits 90, 92 such that air is distributed towardthe side of the user's head 24. For descriptive purposes only, thepresent invention will be described below only in terms of front andrear air exits 90, 92 and will be numbered accordingly. Morespecifically, the front air exits 90 are disposed at the front section94 for distributing air from the air flow channel 34 toward the front ofthe head 24 of the user, and the rear air exits 92 are disposed at therear section 96 for distributing air from the air flow channel 34 towardthe back of the head 24 of the user.

Still referring to FIG. 2, the air flow channel 34 defined between theinner and outer shell portions 30, 32 terminates at the front section 94with the front air exits 90. More specifically, the inner and outershell portions 30, 32 converge toward the front section 94 to define thefront air exits 90. The front air exits 90 may have an air deflector(not shown) defined between the outer shell portion 32 and the innershell portion 30 wherein the outer shell portion 32 angles toward theinner shell portion 30 at the front air exits 90 for proper deflectionof air toward the front of the head 24 of the user. Such an airdeflector is best shown in the '019 patent to Diaz et al., herebyincorporated by reference. The air flow channel 34 diverges uponapproaching the front air exits 90. The convergence and divergence ofthe air flow channel 34 maintains a balanced flow of air about theuser's head 24. Ultimately, this also has the effect of minimizing oreven completely eliminating noise within the helmet assembly 22 due tothe air flow.

The rear air exits 92 are incorporated in a nozzle assembly 98 (alsoreferred to as a duct 98 or a duct assembly 98). Referring to FIG. 9,the nozzle assembly 98 includes a nozzle 100 with rotatably adjustablenozzle tips 102. The nozzle 100 is mounted to the scroll housing 50 suchthat a wall 104 of the nozzle 100 is disposed in the air flow channel 34and diverts air from at least one of the air outlets 76 into at leastone port 106, preferably two. The ports 106 may be referred to herein asconduit-defining discharge members 106, or simply discharge members 106.The ports 106 feed air to the rotatably adjustable nozzle tips 102 andthe rear air exits 92 are defined in the nozzle tips 102. As shown inFIG. 2, the nozzle tips 102 and rear air exits 92 extend below the frontair exits 90 and direct air against the neck of the user, when thepersonal protection system is mounted to the user. As described below,the rear air exits 92 also extend below a head support assembly 108 ofthe helmet assembly 22.

Referring to FIG. 10, each of the nozzle tips 102 includes a nozzle head110 defining the rear air exits 92 of the nozzle tip 102. Each of thenozzle tips 102 also includes a pair of snap-locking fingers 112 forrotatably locking the nozzle tip 102 to the nozzle 100. Referring toFIG. 11 along with FIG. 10, the nozzle 100 includes a inner flange 114disposed in each of the ports 106 and the snap-locking fingers 112 areaxially retained by the inner flange 114 once snap-locked to the nozzle100. The nozzle tip 102 includes an outer flange 116 that abuts a distalend of the nozzle 100 to further axially retain the nozzle tip 102,while a cylindrical shoulder 118 of the outer flange 116 fits inside theport 106 to rotatably support the nozzle tip 102 therein. Thesnap-locking fingers 112 extend from the shoulder. In addition, aplurality of detent fingers 120 extend from shoulder to ride along aplurality of corrugations 122 defined in an inwardly protruding surfaceof the inner flange 114. This allows the nozzle tips 102 to rotate inthe nozzle 100 in a stepped and controlled manner to prevent incidentalrotation of the nozzle tips 102. The nozzle tips 102 can be adjusted tochange the direction of airflow toward or away from the neck of theuser, based on the user's preference. In alternative embodiments, anadjustable deflector (not shown) could be incorporated in the nozzletips 102 to further vary the location on the user's neck at which theair is directed from the rear air exits 92.

The nozzle 100 is preferably formed of ABS, while the nozzle tips 102are preferably formed of LEXAN® polycarbonate. Of course, the nozzle 100and nozzle tips 102 may be formed of other suitable materials known tothose skilled in the art.

Referring to FIGS. 12 and 13, alternative nozzles 100 and adjustable airflow volume mechanisms for use therewith are shown. Referring first toFIG. 12, a first alternative nozzle 100 is shown as including anaperture 124. The aperture 124 is adapted to slidably receive an arm 126of an airflow closer 128 disposed in the air flow channel 34. A user ofthe helmet assembly 22 may adjust the air flow volume out through theports 106, and subsequently through the rear air exits 92 by varying theposition of the airflow closer 128. By sliding the arm 126 in theaperture 124, the user can adjust a position of a baffle 130 of the airflow closer. As the baffle 130 is adjusted toward the air outlet 76 ofthe scroll housing 50, the air flow through the air outlet 76 to thenozzle 100 is reduced, and vice versa. The airflow closer 128 may bepositioned at a fully open position, a fully closed position, or at anynumber of intermediate positions therebetween.

Referring to FIG. 13, the nozzle 100 includes a nozzle vent 132 and theadjustable air flow volume mechanism is in the form of a slider 134. Theslider 134 is movable between a plurality of positions. In a wide openposition, a slider vent 136 in the slider 134 is lined-up with thenozzle vent 132 in the nozzle 100. As a result, a large air flow volumefrom the air outlet 76 of the scroll housing 50 is released from thenozzle 100 before reaching the ports 106. This significantly reduces theair flow volume through the rear air exits 92. In a fully closedposition, the nozzle vent 132 is closed by a panel 138 of the slider 134and the full air flow volume from the air outlet 76 in the scrollhousing 50 is directed to the rear air exits 92. A knob 140 is attachedto the slider 134 through a slot in the nozzle 100 and is used by theuser to vary the position of the slider 134 and control the air flowvolume.

A method of maintaining a constant volume of air flowing into the helmetassembly 22 during or throughout the entire use of the personalprotection system 20 by the user is provided by the present invention.The method includes the step of selectively activating and deactivatingthe power supply as detailed in the '677 patent, which is herebyincorporated by reference.

Referring again to FIG. 3, an adjustable head support assembly 108assists in minimizing the strain on the head 24 and the neck of theuser. Strain and torque on the head 24 and neck of the user is minimizedby maintaining the weight of the fan module 42 over the neck of the usereven upon adjustment of the helmet assembly 22 to fit various sizedheads 24. The head support assembly 108 includes a rear support 142 thatrigidly extends from the shell 28 and is connected to the rear section96. It is to be understood that the rear support 142 can be a separatepart that is connected to the helmet assembly 22 or can be an integralpart of the helmet assembly 22. In the preferred embodiment, the rearsupport 142 is connected to and extends from the rear section 96 of theinner shell portion 30. However, it is to be understood that the rearsupport 142 can connect to and extend from any portion of the shell 28.

Viscoelastic foam pads (not shown) may be applied to the helmet assembly22 at various locations to provide a comfortable barrier between theuser and the helmet assembly 22. In the preferred embodiment, thematerials used to form the helmet assembly 22, particularly thematerials used to form the shell 28, scroll housing 50, and the fan 46,were selected based on their sound-dampening characteristics. Thestiffness of these materials was selected to reduce vibration and changethe frequency of transmitted sound to more appeasing frequencies.

Referring back to FIG. 1, the personal protection system 20 includes ahood 144 for covering the helmet assembly 22, which houses the head 24of the user. The hood 144 operates as a filter medium to filter airbetween the user and the external environment as described in the '019patent, which is incorporated by reference.

Referring now to FIG. 14, the present invention also includes a faceshield 146 that permits the user to view through the hood 144 and thefacial opening 38 of the helmet assembly 22. The face shield 146 mayinclude anti-reflective and/or anti-refractive coatings to enhancevision through the face shield 146. The face shield 146 is mounted tothe hood 144 such that the face shield 146 covers the facial section 36and the facial opening 38 of the helmet assembly 22 once the userdresses into the personal protection system 20. More specifically, theface shield 146 is attached to the hood 144 to maintain a completebarrier between the user and the external environment. The facialopening 38 of the helmet assembly 22 essentially receives the faceshield 146. Preferably, the facial section 36 of the helmet assembly 22includes a hook-and-loop fastener to further facilitate attachment ofthe face shield 146 to the facial section 36 for covering the facialopening 38.

Referring to FIG. 15, the face shield 146 incorporated into the hood 144or gown preferably includes at least one removable or peelable layer 150that provides an easier and effective manner of removing debrisaccumulated on the face shield 146 during use. This will eliminate theneed to wipe the face shield 146 of the accumulated debris during use.In the most preferred embodiment, multiple removable layers 150 areused. These removable layers 150 would be delivered to the user in asterile fashion with the face shield 146 being sterilized between theremovable layers 150 so that no contaminates are present or exposedafter removing the removable layers 150 away from the face shield 146.The removable layers 150 are transparent and preferably flexible. In oneembodiment, the removable layers 150 are thin, flexible, and conform tothe shape of the face shield 146. Furthermore, air gaps between theremovable layers 150 are minimized to reduce multiplereflected/refracted images. Preferably, the removable layers 150 aresterilized using gamma radiation. In the preferred embodiment, the faceshield 146 and removable layers 150 are assembled. The face shield 146and removable layers 150 are then sterilized with gamma radiation. Thesterilized face shields 146 with removable layers 150 are then attachedto the hood 144 in a clean room environment. The hood 144 or gown withthe attached face shields 146 are then individually packaged andsterilized with ethylene oxide.

However, in an alternative embodiment, the removable layers 150 may besterilized with Ethylene Oxide (EtO) gas. In this embodiment, theremovable layers 150 must be breathable for effective EtO gassterilization.

In one embodiment, the removable layers 150 are attached directly to theface shield 146 using a self-adhering method of attachment such asstatic forces, transparent adhesive, and the like. As shown, theremovable layers 150 may include peel tabs 152 that the user or anassistant can grab to peel-away the removable layers 150 from the faceshield 146. The tabs 152 can be positioned at any portion of theremovable layers 150 such as at the top for “peel down” removal, at thebottom for “peel up” removal, or at the side for “peel across” removal.Furthermore, each of the removable layers 150 may have multiple tabs152. The removable layers 150 preferably include anti-reflective and/oranti-refractive coatings to improve vision by reducing multiple images.In one embodiment, the removable layers 150 are formed from a 1 to 5 milclear urethane film. In further embodiments, the removable layers 150are formed of polyester, e.g., Mylar®, or other gamma radiation stablematerials to reduce or eliminate air layers 150 between adjacentremovable layers 150.

In an alternative embodiment, the removable layers 150 are thin andsemi-rigid or rigid and conform to the shape of the face shield 146,while still minimizing the air gap between adjacent removable layers150. The removable layers 150 may be formed as a semi-rigid or rigidfilm. In this embodiment, the removable layers 150 may be attached at aperiphery of the face shield 146 in a non-continuous manner such as byadhesive, tape, spot-welding, static cling attachment, or otherconventional methods of attachment. This allows EtO gas to penetrate theperiphery for terminal sterilization between the removable layers 150.In this embodiment, the removable layers 150 may be manufactured in aflat configuration and then wrapped to conform to the curvature of theface shield 146, which minimizes the air gaps between the removablelayers 150 to reduce unwanted images when looking through the faceshield 146 and the removable layers 150. The removable layers 150 inthis embodiment may also include anti-reflective and/or anti-refractivecoatings to improve vision and may also include tabs 152 to remove theremovable layers 150.

In further embodiments, the removable layers 150, whether thin andflexible or thin and semi-rigid or rigid, may be polarized using apolarized coating. The removable layers 150 may also includemagnification coatings to improve the user's view. Magnification may becarried out solely by the removable layers 150, or in alternativeembodiments, magnification may be carried out by a combination of theremovable layers 150 and the face shield 146. In even furtherembodiments, magnification is carried out solely by the face shield 146.In addition, the removable layers 150 may provide UV protection by usingUV inhibiting films or adhesives.

The face shield 146 may be packaged with multiple removable layers 150ready for removal from the face shield 146 during use. However, in someinstances it may be beneficial to provide a user with greaterflexibility in selecting the types of removable layers 150 to be used,e.g., thin and flexible or thin and semi-rigid or rigid, or to providethe user the option of selecting whether the removable layers 150 willbe used at all. To this end, each removable layer 150 (flexible,semi-rigid, or rigid) is packaged separately from the face shield 146incorporated into the hood 144 or gown. As a result, the user canchoose, which, and how many, of the removable layers 150 to attach tothe face shield 146 prior to use. Alternatively, a removable layer 150(flexible, semi-rigid, or rigid) may be separately packaged and formedwith anti-reflective, anti-refractive, and/or magnification coatings toimprove image quality for the user. In this instance, the coatings maywork with complementary coatings on the face shield 146 to improve theimage quality for the user, or the removable layer 150 may be the solesource of these coatings.

In the event that the removable layers 150 are separately packaged, theywill also be separately sterilized using either EtO gas sterilization,or preferably gamma radiation sterilization. When gamma radiationsterilization is used, the air layers 150 between adjacent removablelayers 150 can be reduced or eliminated, which improves image qualitythrough the removable layers 150. The use of gamma stable materials toform the removable layers 150 also improves optical clarity.

The present invention preferably includes a positioning and supportingsystem for assisting a single user in self-gowning as the user maintainssterility. This system is fully described in the '019 patent to Diaz etal., hereby incorporated by reference. The present invention may alsoinclude a visual positioning system as disclosed in the '019 patent toDiaz et al., hereby incorporated by reference.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. The invention may bepracticed otherwise than as specifically described within the scope ofthe appended claims. In addition, the reference numerals in the claimsare merely for convenience and are not to be read in any way aslimiting.

1. A personal protection unit (20) comprising: a support structure (28)for suspending a hood (144) over the head (24) of an individual; a fanmodule (46) attached to the support structure (28), the fan module (46)receiving air and discharging air; a duct (98) connected to the supportstructure (28) and having an opening positioned to receive the airdischarged from the fan module (46), the duct (98) shaped to have a rearair exit (92); the duct (98) is arranged relative to the fan module (46)so that only a fraction of the air discharged from the fan module (46)enters the duct (98); and the duct (98) extends from the supportstructure (28) and the rear air exit (92) is positioned so that air isdischarged from the rear air exit (92) directly onto the neck of theindividual.
 2. The personal protection unit (20) of claim 1, wherein thesupport structure (28) is a helmet (22) designed to be worn on the head(24) of the individual.
 3. The personal protection unit (20) of claim 2,wherein: the fan module (42) includes a housing (50) in which a fan (46)is seated and the housing (50) has an air outlet (76) from which the airis discharged and the fan module (42) is mounted to the helmet (22) sothat air is discharged from the air outlet (76) away from the head ofthe individual; and the duct (98) is mounted to the helmet (22) todivert air downwardly from the housing (50) to the neck of theindividual.
 4. The personal protection unit (20) of claim 1 wherein: theduct (98) is in the form of a conduit-defining nozzle (100) the rear airexit (92) being at the end of the nozzle (100) distal from the fanmodule (42); and the duct (98) is connected to the support structure(28) so as to extend at least partially over the head (24) so that, whenair is discharged from the fan module (46), the air flows in the nozzle(100), at least partially over the head (24) of the individual, prior todischarge from the rear air exit (92).
 5. The personal protection unit(20) of claim 1 wherein an adjustably positionable tip (102) is fittedto the end of the duct (98) distal to the fan module (46) and theadjustably positionable tip (102) defines the rear air exit (92).
 6. Thepersonal protection unit of claim 1 wherein the duct (98) comprises twospaced apart, conduit-defining discharge members (106), each dischargemember (106) having a rear air exit (92).
 7. The personal protectionunit (20) of claim 5 wherein the adjustably positionable tip (102) isrotatably adjustable for allowing directional adjustment of air.
 8. Apersonal protection unit (20) comprising: a support structure (28) forsuspending a hood (144) over the head (24) of an individual; a fan (46)for circulating air; a motor (48) attached to the support structure(28), the motor (48) connected to the fan (46) for actuating the fan(46); and an elastomeric, vibration dampening member holds the motor(48) to the support structure (28).
 9. The personal protection unit (20)of claim 8, wherein the support structure (28) is a helmet (22) designedto be worn on the head (24) of the individual.
 10. The personalprotection unit (20) of claim 8, wherein: the motor (48) is attached toa rigid motor mount (60); and the elastomeric member includes at leastone motor mount cushion (62) holding the rigid motor mount (60) to thesupport structure (28).
 11. The personal protection unit of claim 10,wherein the motor mount cushion (62) is compression secured to thesupport structure (28).
 12. The personal protection unit (20) of claim10, wherein the rigid motor mount (60) is compression secured to themotor mount cushion (62).
 13. The personal protection unit (20) ofclaims 8, wherein the elastomeric member is a motor mount (60) that issecured to the support structure (26) and to which the motor (48) issecured.
 14. The personal protection unit of claim 13, wherein the motormount (60) is compression secured to the support structure (26).
 15. Apersonal protection assembly (20) comprising: a hood (144) formed offlexible sterilizable material, a portion of which is filter material,and shaped to be worn over the head (24); a transparent face shield(146) attached to the hood (144); a support structure (28) forsuspending the hood (144) over the head (24); a fan (46) attached to thesupport structure for circulating air through the hood; a plurality ofindividually removable layers (150) of sterile transparent material aredisposed over the face shield (146).
 16. The personal protectionassembly of claim 15 wherein each removable layer (150) of transparentmaterial has a tab (152) that allows a user to remove the layer.
 17. Amethod of assembling a sterilized hood assembly having a transparentface shield (146), the method including the steps of: providing a hood(144) formed from sterilizable flexible material, a portion of thematerial being filter material; attaching a transparent face shieldassembly to the hood, the shield assembly including a face shield (146);sterilizing the hood and face shield assembly using a sterilizationprocess that does not adversely affect the filter material; thetransparent shield assembly further includes a plurality of removabletransparent layers (150) disposed over the face shield (146).
 18. Themethod of assembling the sterilizable hood assembly of claim 17,wherein, prior to the step of attaching the transparent shield assemblyto the hood (144); the plurality of transparent layers (150) are appliedto the face shield to form the transparent shield assembly; and thetransparent shield assembly is subjected to a sterilization processseparate from the sterilization process used to sterilize the hood (144)and shield assembly.
 19. The method of assembling the sterilizable hoodassembly of claim 17, wherein an EtO sterilization process is used tosterilize the hood and shield assembly.
 20. The method of assembling thesterilizable hood assembly of claim 17, wherein in the step ofsterilizing the transparent shield assembly, a gamma sterilizationprocess is used.